Maximum fault current limiting electrical circuit-breaker



March 22, 1966 HAYNES I 3,242,287

MAXIMUM FAULT CURRENT LIMITING ELECTRICAL CIRCUIT-BREAKER Filed Oct. 10, 1963 N 2 Sheets-Sheet 1 INVENTOR.

BY fa/er/[Hk7/7 6 March 22, 1966 HAYNES 3,242,287

MAXIMUM FAULT CURRENT LIMITING ELECTRICAL CIRCUIT-BREAKER Filed Oct. 10, 1965 2 Sheets-Sheet z LNVENTOR.

United States Patent 3,242,287 MAXIMUM FAULT CURRENT LIMITING ELEC- TRICAL CIRCUIT-BREAKER Robert E. Haynes, 1925 MillRoad, South Pasadena, Calif. Filed Oct. 10, 1963, Ser. No. 315,243

3 Claims. (Cl. 200106) I This invention relates to a load-break electrical circuit-breaker having inherent maximum fault current limiting Capabilities, the primary object of the invention being to provide an electrical circuit-breaker having sufficient current limiting capabilities to interrupt any electrical circuit under the most severe short-circuit conditions without injury to the circuit-breaker or to the operating personnel.

With the above and other objects in view, which will appear as the description proceeds, the invention resides in the combination and arrangement of parts and in the details of construction hereinafter described and claimed, it being understood that changes in the precise embodiment of the invention herein disclosed, may be made within the scope of what is claimed, without departing from the spirit of the invention.

In the accompanying drawings:

FIGURE 1 is a longitudinal view of the circuit-breaker in the closed position.

FIGURE 2 is a longitudinal view of the circuit-breaker in the open position.

FIGURE 3 is a sectional view taken on line 3 of FIG. 1. Also, other detail parts are shown on the drawing Sheet 2, along the side and below FIG. 3.

FIG. 4 is a sectional view of the solenoid coil 50 and the solenoid plunger 33.

FIG. 5 is a sectional view of the support bar 28.

FIG. 6 is a sectional view of the lever arm 30.

FIG. 7 is a sectional view of the latch pawl bar 35.

FIG. 8 is a sectional view of the trip lever bar 32.

Referring to the drawings in detail, the supporting structure of the circuit-breaker component parts is referred to by the reference character'l, and is composed of insulating or non-conducting material.

Mounted upon the supporting base 1 is a laminated, closed-loop iron core 2. The iron core 2 is separable at the joints 43 and in a similar manner in the other portion of the iron core loop which is mounted within the electrical conducting winding 3. Mounted upon the iron core 2 is an electrical conducting winding 3. The electrical winding 3 has insulation between the winding turns and on the bottom of the winding turns, but no insulation on the outer sides of the winding turns. The electrical winding 3 being precisely machined on the outer surface to form an exact circular outer circumference with no insulation on the outer surface but with insulation around the rest of the winding turns.

Mounted upon one end of the base 1 is a steel spring contact 4 which matches with the opposite contact 5. When the circuit-breaker is actuated the breaker contacts separate and open between the points 4 and 5. The contact point 5 is continuous to the main conductor bar 6 but has a one turn solenoid loop 50 between 5 and 6 for actuating the solenoid plunger stem 33. The main conductor bar 6 is bolted to the supporting bar 28 by the bolt and nut 7. The main conductor bar 6 extends and becomes the first turn of the electrical circuit winding 3. The winding 3 continues turn after turn and ends as the conductor bar 44. The winding 3 has insulation 45 between the turns. The support bar 28 is held to the base 1 by the cap screw 37. The laminated iron core 2 is held to the base 1 by the cap screw 20. The laminated iron core 2 is riveted together by the rivet 21.

3,242,287 Patented Mar. 22, 1966 A semi-cylindrical short-circuiting body 12, as shown in the cross section of FIG. 3, is hinged at the joint 16 and in the closed position of the circuit-breaker, the body 12 short-circuits each turn of the winding 3 by making physical contact with the outer bare edges or sides of the winding 3. The body 12 is a conducting material having sufiicient spring tension to form a tight contact from contact to contact of each turn of the winding 3. The hinged bar 10 extends through and is bolted to the body 12 by the bolts 11. The right end of the bar 10 has a contact 51 which further short-circuits the Winding 3 and by-passes the entire circuit of the winding 3, when the body 12 is held in its maximum closed position and the contact 10 is held firmly against the main conductor bar 6.

When the circuit-breaker is in its closed position, the electrical current enters at the line terminal 39, which is bolted to the base 1 by the cap screw 42, and travels through the contacts 4 and 5 to the main conductor bar 6 to the by-pass contact and bar 10 to the stranded flexible conducting bar 15, which is bolted to the by-pass bar 10 by the bolt and nut 14. The flexible conducting bar 15 is bolted to the load-side conductor bar 44 by the bolt and nut 16. The load-side terminal connection 17 is provided for connection of the utility branch-circuit conductor. The supporting bar 19 supports the hinged joint 16 and the load-side conductor bar 44 and is bolted to the base 1 by the cap screws 18.

The contact point and spring 4 has a slight tendency to hold its self in the closed contact position with the opposite contact point 5. The spring bar 40 is stronger than the spring bar 52 holding the contact 4 and when released will hold the contact 4 separated from the opposite contact point 5. The spring 41 has a tendency to hold the spring contact 4 to the stronger spring 40. Both springs 40 and 52 are held in place by the cap screw 42. An insulating connecting lever 31 is hinged to the spring 40 and to the cross linkage lever arm 30. The connecting lever 29 is hinged to the lever arm 30 and to the insulating block 8, which is held to the bypass bar 10 by the cap screw 9. The lever 29 is connected to the lever 23 by the short lever linkage 27. The lever 23 is hinged to the operating lever 13. The latch pawl 24 is hinged to the operating lever 13. The operating lever 13 is hinged to the block 21, which is held to the base 1 by the cap screw 22. The spring 26 hasa tendency to hold the latch pawl 24 in the latch position to the lever 23, so that the operating lever 13 can close the circuit-breaker. The spring-like lever 25 is flexible in nature and hinges to the trip lever 32.

The latch pawl 35 is hinged to the support bar 28. The latch pawl 35 has an arm 36, which is in near-contact with the spring lever 25. The latch pawl 35 is held in the latch position by the spring 38. When the operating lever 13 is moved counterclockwise to open the circuit-breaker, the linkage 27 will kick out to one side and the spring lever 25 will rotate the arm 36 clockwise, causing the latch pawl 35 to release the levers connected to the arm 30, thereby allowing the strong spring 40 to open the circuit-breaker.

In the actual operation of this maximum fault current limiting circuit-breaker, the electrical current enters at the terminal connection 39 and travels through the contact points 4 and 5 to the main conductor bar 6 and along the bar 6 to the contact point and bar 10, then through the conductor bar 10 to the stranded flexible bar 15 to the outlet and terminal connection bar 17. In the closed position, little, if any, electrical current passes through the winding 3, or the winding shortcircuiting body 12.

When a short-circuit condition occurs on the loadside of the circuit-breaker, the tremendous inrush of electrical current through the circuit-breaker current carrying path causes the solenoid plunger and stem 33 to raise the circular cross bar 34, which in turn lifts the trip lever 32, which actuates the latch lever 35 to release the cross lever arm 30, thereby allowing the strong spring 40 to trip the circuit-breaker into the open position, through the actuation of the parallel operation of the levers 31, 30 and 29.

As the lever arm 30 is released, the slight movement of the lever 29 will open the contact between the bypass short-circuiting bar and the main conductor bar 6, which in turn puts the entire short-circuit path of current through each parallel turn of the winding 3 to the shortcircuiting body 12. As the lever arm 29 lifts the shortcircuiting body 12 further away from the winding 3, toward the maximum open position of the circuit-breaker, each one half turn of the winding 3 is consecutively, one after the other, placed into the full flow current carrying path of the circuit-breaker. When the entire winding 3 is placed in the current carrying path of the circuitbreaker, the winding 3 acts as, or in the same manner as, a transformer winding, creating a counter electromotive force by the alternating current inductive lines of force circulating through the winding and the iron laminated core. The counter electromotive force in the winding 3 limits the further passage of the inrush short-circuit current. At or about the instance the entire winding 3 is placed into the current carrying path of the circuit-breaker path, the spring 40 has traveled far enough to open the contact points 4 and 5.

The entire opening operation of the circuit-breaker is, for all practical purposes, instantaneous. Because the en tire winding 3 is placed into circuit path almost instantaneously, each one half turn after the other, because each one half turn is one half the distance between each turn of the winding 3, the impedance between each one half turn of the winding 3 is extremely small and this allows .the entire short circuit inrush current to divide quite evenly between the turns of the winding 3 and the short-circuiting body 12, as the body 12 opens and places each turn of the winding 3 into the short-circuit path.

To close the circuit-breaker, after the circuit-breaker has been tripped, the operating lever 13 is moved back to engage the latch pawl 24 with the lever 23, so that the operating lever 13 can be moved forward so that the lever 23 will pull the linkage 27 which in turn closes the circuitbreaker points and contacts 4 and 5 by the movement of the levers 29, 30 and 31. If the circuit-breaker is closed under a short-circuit condition, the entire tripping mechanism will instantly function and move the spring arm 25 which will in turn release the latch pawl 24, which in turn releases the lever arm 23 allowing the circuit-breaker to open. The lever arm 23 has an ofi-set edge 53 which catches under the latch pawl 24, allowing the operating lever 13 to move the lever 23.

Having thus described the invention, what is claimed is:

1. In a maximum fault current-limiting electrical circuit-breaker, the combination comprising breaker contact points, an electrical circuit winding, a movable semicylindrical body, said breaker contact points and said electrical circuit winding forming a series circuit path, said movable semi-cylindrical body forming successive short-circuiting path contacts between consecutive turns of said electrical circuit winding, means for closing said breaker contact points and moving said semi-cylindrical body to form s ccessive hQ.rt-circuiting P th co t ts between consecutive turns of said electrical circuit winding for normal circuit current operation, means for releasing said semi-cylindrical body and removing successively said short-circuiting path contacts between consecutive turns of said electrical circuit winding and opening said breaker contact points for abnormal circuit current operation.

2. A maximum fault current-limiting electrical circuitbreaker, embodying the combination of breaker contact points, an electrical circuit winding, the breaker contact points being connected in series with said electrical circuit winding, a semi-cylindrical body, said semi-cylindrical body being mounted at one of its ends to align evenly tomake contact with the outermost portion of each turn; of said electrical circuit winding, said semi-cylindrical body being supported at said end in such a manner that the other end moves upwardly and away from said electrical circuit winding before said support end, said semicylindrical body being of conducting material and having a fixed connection at one end and a contact point at the other end for bypassing said electrical circuit winding when said semi-cylindrical body is in its closest contact with said electrical circuit winding, means for moving said semi-cylindrical body into contact with said electrical circuit winding and closing said breaker contact points, means for releasing said semi-cylindrical body from said electrical circuit winding and opening said breaker con tact points, said releasing means comprising latching means, a solenoid and a solenoid plunger, said solenoid being energized by the current through said electrical circuit winding to actuate said plunger and releasing said latching means. 1 a

3. In an electrical actuated maximum fault current limiting circuit-breaker, the combination of breaker contact points, an electrical circuit winding, a short-circuiting component, said breaker contact points and said electrical circuit winding forming a series circuit path, said short-circuiting component beng mounted to form successive short-circuit contacts from the first turn of said electrical circuit winding through each following conse cutive turns of said electrical circuit winding, means for closing said breaker contact points and moving said short circuiting component to form successive short-circuit contacts from the first turn of said electrical circuit winding through each following consecutive turn of said electrical circuit winding for normal circuit current operation, means for releasing said short-circuiting component and removing successively the short-circuit contacts from the last turn of said electrical circuit winding through each following consecutive turn of said electrical circuit winding for abnormal circuit current operation.

References Cited by the Examiner UNITED STATES PATENTS 260,623 7/1882 Starr 33893 470,161 3/1892 Wurts. 3,192,338 6/1965 Haynes 200-106 X FOREIGN PATENTS 619,689 10/1935 Germany.

11,168 11/1904 Great Britain.

BERNARD A. GILHEANY, Primary Examiner.

T. D. MACBLAIN, Assistant Examiner. 

1. IN A MAXIMUM FAULT CURRENT-LIMITING ELECTRICAL CIRCUIT-BREAKER, THE COMBINATION COMPRISING BREAKER CONTACT POINTS, AN ELECTRICAL CIRCUIT WINDING, A MOVABLE SEMICYLINDRICAL BODY, SAID BREAKER CONTACT POINTS AND SAID ELECTRICAL CIRCUIT WINDING FORMING A SERIES CIRCUIT PATH, SAID MOVABLE SEMI-CYLINDRICAL BODY FORMING SUCCESSIVE SHORT-CIRCUITING PATH CONTACTS BETWEEN CONSECUTIVE TURNS OF SAID ELECTRICAL CIRCUIT WINDING, MEANS FOR CLOSING SAID BREAKER CONTACT POINTS AND MOVING SAID SEMI-CYLINDRICAL BODY TO FORM SUCCESSIVE SHORT-CIRCUITING PATH CONTACTS BETWEEN CONSECUTIVE TURNS OF SAID ELECTRICAL CIRCUIT WINDING FOR NORMAL CIRCUIT CURRENT OPERATION, MEANS FOR RELEASING SAID SEMI-CYLINDRICAL BODY AND REMOVING SUCCESSIVELY SAID SHORT-CURCUITING PATH CONTACTS BETWEEN CONSECUTIVE TURNS OF SAID ELECTRICAL CIRCUIT WINDING AND OPENING SAID BREAKER CONTACT POINTS FOR ABNORMAL CIRCUIT CURRENT OPERATION. 